#!/usr/bin/env python
#__*__ coding: utf-8 __*__

import pygame,sys,time,random
from random import randrange
from pygame.locals import *


redColour = pygame.Color(255,0,0)
blackColour = pygame.Color(0,0,0)
whiteColour = pygame.Color(255,255,255)
greyColour = pygame.Color(150,150,150)

def gameOver(playSurface):
        gameOverFont = pygame.font.SysFont('SimHei',72)
        gameOverSurf = gameOverFont.render('Game Over', True, greyColour)
        gameOverRect = gameOverSurf.get_rect()
        gameOverRect.midtop = (320, 10)
        playSurface.blit(gameOverSurf, gameOverRect)
        pygame.display.flip()
        time.sleep(5)
        pygame.quit()
        sys.exit()

def main():
	pygame.init()
	playSurface = pygame.display.set_mode((640,480))
	fpsClock = pygame.time.Clock()
	pygame.display.set_caption('Snake Liu')

	snakePosition = [100,100]
	snakeSegments = [[100,100],[80,100],[60,100]]
	raspberryPosition = [300,300]
	raspberrySpawned = 1
	direction = 'right'
	changeDirection = direction
	while True:
		for event in pygame.event.get():
			if event.type == QUIT:
				sys.exit()
			elif event.type == KEYDOWN:
				if event.key == K_RIGHT or event.key == ord('d'):
					changeDirection = 'right'
				if event.key == K_LEFT or event.key == ord('a'):
					changeDirection = 'left'
				if event.key == K_UP or event.key == ord('w'):
					changeDirection = 'up'
				if event.key == K_DOWN or event.key == ord('s'):
					changeDirection = 'down'
				if event.key == K_ESCAPE:
					pygame.event.post(pygame.event.Event(QUIT))
		# 判断是否输入了反方向,与原文有改动
		if changeDirection == 'right':
			direction = changeDirection
		if changeDirection == 'left':
			direction = changeDirection
		if changeDirection == 'up':
			direction = changeDirection
		if changeDirection == 'down':
			direction = changeDirection
		# 根据方向移动蛇头的坐标
		if direction == 'right':
			snakePosition[0] += 20
		if direction == 'left':
			snakePosition[0] -= 20
		if direction == 'up':
			snakePosition[1] -= 20
		if direction == 'down':
			snakePosition[1] += 20
		# 增加蛇的长度
		snakeSegments.insert(0,list(snakePosition))
		# 判断是否吃掉了树莓
		if snakePosition[0] == raspberryPosition[0] and snakePosition[1] == raspberryPosition[1]:
			raspberrySpawned = 0
		else:
			snakeSegments.pop()
		# 如果吃掉树莓，则重新生成树莓
		if raspberrySpawned == 0:
			x = random.randrange(1,32)
			y = random.randrange(1,24)
			raspberryPosition = [int(x*20),int(y*20)]
			raspberrySpawned = 1

		# 刷新显示层
		playSurface.fill(blackColour)
		for position in snakeSegments:
			pygame.draw.rect(playSurface,whiteColour,Rect(position[0],position[1],20,20))
			pygame.draw.rect(playSurface,redColour,Rect(raspberryPosition[0], raspberryPosition[1],20,20))
		pygame.display.flip()

		# 判断是否死亡，后面几行和原文有改动
		if snakePosition[0] > 620 or snakePosition[0] < 0:
			gameOver(playSurface)
		if snakePosition[1] > 460 or snakePosition[1] < 0:
			gameOver(playSurface)
		for snakeBody in snakeSegments[1:]:
			if snakePosition[0] == snakeBody[0] and snakePosition[1] == snakeBody[1]:
				gameOver(playSurface)
		fpsClock.tick(5)
if __name__ == "__main__":
	main()
